7 



Sulphate of quinine is fatal at a strength of one in 2,000, and borax and boric acid at the same 



dilution. . 



One objection to copper sulphate is that the solution becomes condensed by evaporation and crys- 

 tals deposited on the leaf, which burn it and make it look unsightly, especially when used for a long 

 time consecutively. This, however, may be obviated by the addition of a little sugar which prevents 

 crystallization, at least to a large extent. 



Tobacco water, however, does not damage the leaves at all. It is more expensive than copper 

 sulphate, but, of course, refuse tobacco can be used for the purpose and is cheap enough in Java. The 

 liquid is applied by a spray diftusor to the under surface ot the leaves, any fungus already there is, of 

 course, killed at once and as the liquid becomes condensed by evaporation a thin layer of tobacco ex- 

 tract is left on the leaf. The next rain or dew re-dissolves the extract and this prevents the spores which, 

 fall upon the leaf from germinating ; gradually, of course, the rain washes away part of the tobacco and 

 it is, therefore, necessary to treat the plant again. Tobacco water does not remain as long on the leaf 

 as copper sulphate or iron chloride. 



Treatment of young Plants. 



Young plants as is well known are very liable to disease, and they often let fall a great part of 

 their leaves before they have been transplanted to the open ground from the nursery. 



This is partly due to the crowding of the little plants together and also to the necessity of sprink- 

 ling them with water during the dry season, and the slow evaporation of the water from the plants 

 under cover. The sprinkling should be done twice a week. Plants treated like this were found to be 

 free from disease, except where by some accident the tobacco water did not touch the leaf, although they 

 might be surrounded by untreated plants which were extensively affected. Indeed th- chance of in- 

 fection then is so great that a leaf only partially wetted was sure to get ill. 



It cannot be too much urged to commence sprinkling before the disease appears. If you wait till 

 the yellow spots appear you lose many leaves without necessity. It must be remembered that when 

 the disease is once visible on the lower leaves it is certain that one or two pairs of higher leaves are 

 attacked and will shew the spots in a few days. You cannot save these leaves, you can only prevent 

 the disease goi:ig further. It is thus possible to plant out all the young shrubs into the plantation free 

 of disease and without the loss of a single leaf. After the plants are removed to the plantation, they 

 must still be protected by means of the scissors or sulphuric acid bottle, and also the tobacco water. A 

 cooly is instructed to examine each plant twice a month and to destroy with acid or scissors each sick 

 spo', and, of course, one man can look after a very large number of plants, especially if the work is 

 commenced immediately the plants leave the nuisery. Usually the disease commences on each plane 

 sporadically, gradually spreading afterwards, so that if each primitive spot is at once removed, not only 

 do you prevent any secondary attack, but atao keep the disease sporadic and prevent a strong attack. 

 The cost of sprinkling each plant with tobacco water twice a week was at Buitenzorg 1 cent (guilder) 

 per year for labour and about T \j cent for refuse tobacco. Dr. Burck used one " lempeng" of tobacco 

 in a kerosine tin of 18 litres. The tobacco was put in the evening before use in warm water. Two 

 kerosine tins were enough for 1,000 plants. As the plants get older, of course, the expenses are greater 

 but the cost of treatment of a plant from the time of sowing in the nursery till it begins to fruit will 

 rarely be more than 1 \ guilder cents. 



The Use of Hedges against the Disease. 



An examination of a thirteen-year old coffee garden at Buitenzorg shewed that the North-west 

 side was badly attacked by disease, but it decreased on the North-east, East and South sides of the plan- 

 tation in proportion to the distance from the North-west side, and again the bushes in the interior of 

 the plantation were less badly attacked than those of the outside. Now the prevailing wind here is from 

 the North-west, and it seems evident from this that the more a plantation is exposed to the prevailing 

 wind the more it is liable to be affected. Further examinations shewed that the interior of the planta- 

 tion is less attacked than the exterior. From this it is clear that the planting of a close hedge of coffee 

 trees which by means of tobacco water is protected against disease and loss of leaves, is of the greatest 

 importance in protecting the plants enclosed by the hedge from disease or at least will keep it in a 

 sporadic state; of course more than one hedge will have to be planted where the ground is broken. The 

 number and position of the hedges will depend on the circumstances of each plantation, and each Mana- 

 ger will have to judge of this for himself, remembering that the great object is to prevent one patch or 

 plantation being affected by wind dispersal of spores from another. The hedges should be as close and 

 thick as possible, but even if not quite close the disease in the rows of trees enclosed will not even be so 

 bad as not to be easily preventable by the repressive method if necessary. By this means should the 

 hedges be as successful as there is every reason to believe they will prove to be the much dreaded disease 

 may be simply and inexpensively combated. 



Spray Diffusers. 



Two of these have been invented in Java for throwing the tobacco water or copper sulphate over 

 the plants in the form of a tine spray. Of these, one made by the French firm Broquet for the mildew 

 disease of the vines in France was found to work very well except for the great quantity used on ea 

 tree, i.e., 1 litre The chief objection to this was that it entailed the carrying about of such large 

 quantities of the liquid and this was very cumbersome. For small patches and in cases where it is 

 only requisite to sprinkle the dividing hedges, this instrument does very well. The Chief Engineer 

 of the Public Works Department, T. Van Schaik, and H G. Derx, Chief Inspector of Railways, in- 

 Tented a machine which was superior in possessing a stronger pump and using less liquid ; with thi a 

 instrument a coolie could work tor the whole day with two petroleum tins of liquid, about 36 litree. 



